Electron discharge device



Aug. 22, 1939. w. H. PAINTER 2,170,633-

BLECTRON DIS CHARGE DEVICE Filed March 30 1935 2 Sheets- Sheet 1INVENTOR WILLIAM H. INTER BY 7 AT'TRNEY Aug. 22, 1939. w. H. PAINTER 3ELECTRON DISCHARGE DEVICE Filed March 30, 1935 2 Sheets-Sheet 2 5. IIIII I INVENTOR WILLIAM H. PAINTER Patented Aug. 22, 1939 UNITED STATESPATENT OFFICE ELECTRON DISCHARGE DEVICE tion of Delaware ApplicationMarch 30, 1935, Serial No. 13,854

5 Claims.

My present invention relates in general to an improvement in electronic.tube structure and more particularly relates to the mounting ofelectron beam generating, focusing, and accelerating electrodes withinan electronic device of the cathode ray type. It has been customary inthe past to provide in an electron tube of the cathode ray type astructure of electrode elements within the tube by mounting certain ofthe elements comprising the electron gun upon a reentrant stem. Toprovide electrical contact with these elements lead wires and spuds wereprovided in the glass press and the elements were individually andseparately attached to these lead wires by welding or other suitablemeans. The resultant structure had the disadvantage that the electrodemembers were in many instances non-rigidly supported and that relativemotion was possible between the various elements It is well known in thecathode ray art that accuracy of alignment and spacing of the varioustube parts is a prerequisite to efficient operation and that suchalignment and spacing has been exceedingly difficult to obtain by theconventional means of support.

Therefore, in accordance with my invention, I have provided a cathoderay'device having novel structural features which increase the rigidityof the assembly and thereby improve the operating characteristics of thedevice. Also, in-accordance with my invention, it is possible to provideclose electrode spacings which heretofore were very difiicult to obtain.

Having in mind the defects of prior art tubes, it is an object of myinvention to provide improved supporting means for the elements of acathode ray tube. It is a further object of my invention to provide anelectron tube electrode assembly having the component partsconcentrically mounted in a predetermined spaced relationship.

My invention possesses numerous other objects and features which will beset forth in the following description of the invention, and, as willbecome apparent from reading the specification, many modifications andchanges in form may be provided so that I do not intend to limit myselfto the specific modifications shown, but believe myself to be entitledto adopt variantembodiments of the invention which fall fairly withinthe spirit and scope of the appended claims.

The novel features that I consider characteristic of my inventiontogether with the invention itself will best be understood from thefollowing description of certain preferred embodiments thereof when readin connection with the accompanying drawings in which,

Figure 1 is a View of a cathode ray tube in side elevation embodying onemodification of my invention;

Figure 2 is an axial sectional View of one modification of my invention;and,

Figure 3 is an axial sectional view of a second modification of myinvention.

If reference is now made to the drawings it Will be seen that theforegoing and auxiliary objects are attained by providing according toapreferred embodiment of my invention, a concentric electrode assemblyunit by the use of suitable insulating spacers so positioned as to holdthe electrodes in a single unit assembly. Specifically the oathode,control grid and electron accelerating elements are provided withflanges whereby these elements are rigidly supported by means ofinsulating compression members. The electrodes are held rigid by thespacers serving as compression members in the assembly and the entireunit is then supported as a whole from the stem press insuring a maximumof rigidity among the component parts.

Referring now more particularly to the accompanying drawings the cathoderay device comprises the usual sealed and evacuated vessel l0 having asubstantially cylindrical neck section I! and a frusto-conical sectionl4 terminated by a substantially plane surface it. The reentrant stempress it is used to support the electron gun assembly 20. The electrongun assembly, as shown in more detail by Figure 2, comprises thefilament or heater 22, a cathode and control grid assembly 24, anaccelerating electrode assembly 26 and an anode assembly 28. Suitablesupport leads 3ll-32, one of which may be a current carrying lead,support the gun assembly from the reentrant stem press.

The sub-assemblies, enumerated above, may have current carrying leadsdesignated as 34, 36, 38, and Ml respectively. The tube Ill, preferablyhas incorporated therein beam deflecting plates 42 and 44, which byimpressing suitable operating 45 potentials thereon may be made todirect the beam over various portions of the luminescent screen 46deposited on the inner wall of the end section I6. An auxiliary beamfocusing electrode surface 48 is provided on a portion of the inner wall50 of the vessel terminating in a current carrying lead 50'.

That embodiment of my invention shown in Figure 2, as alreadyconsidered, comprises the cathode-control grid assembly 24, accelerating55 electrode assembly 26, and anode assembly 28. It will be seen onreference to the drawing that the cathode-control grid assemblycomprises the cylindrical sleeve 52 surrounded by the supporting discThe cathode 23 is provided with an indentation 25 which may containelectron emissive material such as barium or strontium compounds.

The insulating disc 60 is provided with holes 62 thru which may bethreaded the filament leads 34 and the cathode lead 36. The cathode isrigidly supported between this disc 60 and'a recessed insulating disc64. These two insulating members are held by compression between theflanged member 66 and the apertured flanged control grid disc 68. Thecathode is thus held securely by compression within a predeterminedaxial distance of the control grid disc, such distance depending uponthe recess in the insulator 64.

The cathode-control grid assembly 24 is rigidly secured to theaccelerating grid assembly 26 in much the same manner as the cathode waspositioned within the control grid assembly. The annular apertured disc5 carrying the cathodecontrol grid assembly is positioned and spacedfrom the apertured flanged disc 10, which forms the effectiveaccelerating electrode surface, by the insulating members 72 and M.These insulators are supported in compression between the flangedmembers 79 and 18; the entire assembly being retained by the cylindricalsleeve 18.

In like manner the accelerating grid-control grid assemblies aresupported by the insulating members 8!] and 82 between the flanged discs84 and 88 which are supported in turn by the anode assembly 28comprising the cylindrical sleeve 88 and apertured discs 90, 92, and 94.

A further embodiment of the structure shown in Figure 2 is that shown inFigure 3 wherein the various component parts have similar designations.The cathode-control grid assembly 24 is for all practical purposes thesame as that shown in Figure 2 comprising the heater 22, cathode 23supported by the insulating spacers 60,

. 64 between the apertured discs 66, 6B and cylindrical sleeve 52. Inthis modification the entire gun assembly 20 is supported from the stempress l8 by the accelerating electrode assembly 26 through the supports30, 32 rather than through the anode assembly 28.

The accelerating electrode assembly thus rigidly fixes the position ofthe cathode-control grid assembly 2G by insulating members 72, M and theanode assembly by the insulating members 80, 82. insulating members 72,M, 80, 82 by compression between the flanged discs 26, 98, IEO, whichare fastened to the accelerating electrode cylinder 78 by welding orother suitable means. In this modification (Fig. 3) provision may bemade to supply operating potential to the anode 28 through the flexiblecurrent carrying lead IM. The entire electron gun assembly 20, as asingle unit, may be supported by the stem l8 through the rods 32. Thecurrent carrying lead I 04 being This rigidity is insured by holdingthe.

flexible will furnish no material support for the anode, that elementbeing supported by the aforementioned insulating spacers.

It will be apparent to those skilled in the art that the electron gunassembly may be supported from the stern in a number of ways, such as byrods extending to the control grid assembly rather than to the anode oraccelerating electrode assembly.

What I claim is:

1. A cathode ray discharge device comprising an enclosing envelopehaving a stem, a plurality of rods extending from said stem, an anodemounted on said rods, said anode partially enclosing a cathode, controlelectrode and accelerating electrode mounted in concentric relation withsaid anode and supported thereby independently of said stem.

2. A cathode ray discharge device comprising an enclosing envelopehaving a stem, a plurality of rods extending from said stem, anaccelerating electrode mounted on said rods, said accelerating electrodepartially enclosing a cathode and a control electrode and an anodemounted in coaxial relation with said accelerating electrode andsupported thereby independently of said stem in a position to at leastpartially house all of said electrodes.

3. A cathode ray device comprising an enclosing envelope having a stem,a plurality of rods extending from said stem, a control electrodemounted on said rods, said control electrode supporting in compressionbetween concentric insulating spacers, and in coaxial relationtherewith, a cathode, accelerating electrode and anode, and said anodebeing positioned at least partially to surround all of said electrodes.

e. A cathode raydevice comprising an enclosing envelope having a stem, aplurality of rods extending from said stem, an anode mounted on saidrods, said anode supporting in compression between concentric insulatingspacers, and in concentric relation therewith, a cathode, controlelectrode and an accelerating electrode, said electrode control,accelerating electrode and anode each having apertures located in.alignment with the cathode, said apertures being of different diameters.

5. An electron tube comprising an enclosing envelope having a stemmember at one end thereof, a plurality of current carrying supportmembers secured within the stem portion and protruding inwardly of theenvelope, a cold electrode member supported rigidly from the inwardlyextending support members and a cathode member also positioned withinsaid envelope and at least partially surrounded by the rigidly supportedcold electrode, and a plurality of additional cold electrodes rigidlysupported from the first named cold electrode independently of thesupport stem and in concentric relationship with the first namedelectrode and the cathode, and also at least partially housing saidfirst named electrodes.

WILLIAM H. PAINTER.

